fuller



March 31, 1964 H. L. FULLER 3,125,356

MOTOR BOAT HULL Filed July :5, 1962 I 2 sheets-sheet 1 March 31, 1964 H. L. FULLER MOTOR BOAT HULL 2 Sheets-Sheet 2 Filed July 5, 1962 n a., w M M H INVENTOR United States Patent O 3,126,856 MOTOR BAT HULL Harold L. Fuller, PA). Box 566, Lake Isabella, Calif. Fried my s, 1962, ser. N0. 207,335 7 Ciaims. (Cl. 114-665) This invention relates to motor boat hulls, more particularly to hulls adapted to be driven by outboard motors.

Included in the objects of this invention are:

First, to provide a motor boat hull wherein the bottom of the hull is provided with a plurality of essentially flat ski-like ribs of uniform width from bow to stern separated by channels ialso Yof uniform width, the depth of the channels being such 4as to form continuous |air passages under the hull.

Second, to provide a motor boat hull wherein a relatively wide ski rib is disposed in centered relation to the axis -of the propeller so that the water approaching the propeller is substantially 'free of air, thereby decreasing cavitation and increasing propeller thrust.

Third, to provide a lmotor boat hull which is adapted to be formed of fiber glass material, and wherein -an inner and outer hull deiine longitudinal 4cavities adapted to be lled with a rigid, foamed plastic, which, when bonded to the encasing hulls, provides a particularly strong, as well las buoyant, huli structure.

Fourth, to provide a hull `structure Which is relatively wide with respect to Iits length and is essentially flat throughout its major surface, in both -a longitudinal and a transverse direction so that the hull is virtually capsizeproof and therefore particularly suited Afor use by amateurs, this being accomplished without loss of, but, instead, improved operating efficiency.

Fifth, to provide a hull structure, which, by reason of is high width-to-length ratio, provides a large area for passengers and equipment and permits incorporation of a wide variety Aof superstructures.

Sixth, to provide la motor boat hull structure rwhich, although having a relatively high width-to-length -ratio and although the ski surfaces dene a flat bottom, the air ducts or passages between the ski surfaces ensure a cushioned ride.

With the above and other objects in view, las may appear hereinafter, reference is directed to the accompanying drawings in which:

FIGURE 1 is a side view of the motor boat hull;

-FIGURE 2 is a bottom view thereof;

FIGURE 3 is a rear end view thereof;

FIGURES 4 and 5 are longitudinal, `substantially diagrammatical, sectional views taken through 4-4 and 5-5 of FIGURE 2;

FIGURE y6 is an enlarged, transverse, sectional view taken through 6-6 of FIGURE v2,

FIGURE 7 is a rear view showing a modied -form of the -hull adapted for operation by two outboard motors.

Reference is first directed to FIGURES 1 through 6. In the construction here illustrated, there is provided an outer hull 1 formed of -impregnated fiber glass. The outer hull 1 includes -a center ski rib 2, the forward end of which curves upward to the bow 3` of the hull.

The center ski rib 2 is uniform in width throughout its length, and, preferably, in cross section defines a shallow, obtuse V. The two sides of the center ski rib 2 rare flanked by air duct channels 4, also of uniform width, and

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extending the full length of the hull from the bow to the ste-rn.

Later-ally of each air duct vchannel 4 is an intermediate ski rib 5, each of which is somewhat narrower than the center :ski rib 2. The intermediate ski ribs 5 are of uniform width from -bow to stern, land their under surfaces preferably define a shallow V. A second pair of air duct channels 6 are provided laterally of the ski ribs 5. These lllc `are of uniform width, and extend the length of the `Laterally of the air ducts `6 is a pair of lateral ski ribs 7. At the rear of the boat the ski ribs 7 have hat portions 8 bordered by laterally and upwardly sloping walls 9. As the iiat portions 8 of the ski ribs 7 extend forward they fade out or merge into the sloping walls 9.

At points midway or slightly forward of the center `of the -hull 1, the lateral ski ribs 7 are downwardly extended to form sponsons 10. The sponsons are provided with dat portions 11 and their forward ends curve upwardly. The flat portions '11 Iof the sponsons are joined to outwardly and upwardly sloping Walls 12, disposed at a somewhat steeper angle than the sloping walls 9i.

The sloping Walls -9 and 12 are joined to vertical side Walls 13 which Iare parallel to each other except at the bow of the boat, in which region they curve toward each other. The hull 1 is therefore of uniform Width except at its bow region. Formed at the juncture of the sloping walls with the vertical side walls 13 -are downwardly racing, `longitudinal `groove-s which Iform spray rails 14.

The rear end of the hull 1 is closed by a transom 15. The upper margins of the transom 15 and the vertical side Walls 13 are flared outwardly to form a marginal rim 16. The rim 16 extends into the bow region of the hull 1, and in this region attenuates toward-s the tip of the bow 3. The transom 15 is provided with a central reinforced portion 17 arranged for the mounting of an tutboard motor or an inbound-outboard motor.

At suitable locations, the margin-al rim 16 may be provided w-ith handle recesses 18.

As shown in FIGURE 6, the outer hull 1 receives an inner hull 19, also formed of ber glass. The bottom of the inner hull 19 rests on the internal ribs formed by the air duct channels 4 and 6, and bridge over the ski ribs 2, 5, and 7, as Well as the sponsons 10, so that longitudinal cavities are formed. These cavities receive a rigid, foamed plastic iiller 20 which bonds to the hulls 1 and 19. In addition, in those regions where the hulls are in contact with each other, they are suitably bonded together so that, when completed, a unitary hull structure is formed, having great strength in comparison to its weight; and, in fact, may be so constructed as to have a density less than water to ensure that the hull will iloat even if lled with water.

In addition to the reinforcing provided by the inner hull 19, one or more transverse ribs or partitions 21 are provided. The location and arrangement of the transverse ribs depends upon the superstructure, seating arrangement, and accommodations for equipment which may be added to the hull, but which are omitted from the drawings.

In the construction shown in FIGURES l through 6, the hull is intended to be driven by a single, centrally located motor, the propeller of which is located in a longi- 3 tudinal axis centered with respect to the center ski rib 2, as indicated by broken outline Ain FIGURE 3.

The depth of the air duct channels 4 and 6, the proportions of the ski ribs 2, 5, and 7 and sponson l0, and the overall weight of the hull, together with whatever superstructure may be added, are so related that, when the hull is in motion, air is entrapped in the channels and iiows under the hull. Most of the air, which might be otherwise entrapped under the skis, tends to concentrate in the air duct channels. In the region downwardly of the center rib 2, the water is essentially air free, and therefore the propeller at the rear end of the center rib 2 rotates in essentially air-free water, so that cavitation effects are minimized and maximum thrust is obtained.

The slightly inverted V cross section of the faces of the ski ribs cause these ribs to retain a slight quantity of air. That is, air in an insuicient amount to affect the Water thereunder, but sufficient to act as an air bearing between the water and the hull, and to minimize skin friction.

Because of the high width-to-length ratio, and, additionally, because of the substantial buoyant regions formed between the hulls alOng the lateral sides thereof, particularly in the regions of the sponsons it?, itis virtually impossible to capsize the hull, even when the boat is carelessly maneuvered by an amateur. It will also be observed that, although the bottom of the hull is essentially flat, substantial vertical areas are provided by the ski ribs and sponsons so that on turning maneuvers the hull resists lateral skidding.

It will be noted that the ski ribs 2 and 5 and the air duct channels 4 and 6 are of uniform widths throughout their lengths so that, as the hull passes over the water, there is virtually no lateral displacement of the water and no compressive forces are exerted. What water is displaced laterally is displaced only a short distance into the channels, is broken up, and is intermixed with the air therein. The net effect is to reduce drag and improve the overall efficiency of the hull, yas well as to provide a cushioned ride.

Reference is now directed to FIGURE 7. The essential difference here is that the hull illustrated is adapted to be driven by two outboard motors. For this purpose the central ski rib 2a is made narrower than the corresponding rib 2 of the first described structure, and the intermediate ski ribs a are made wider than the corresponding ski ribs 5 so as to provide two regions of air- Vfree water in front yof the two propellers While particular embodiments of this invention have been shown and described, it is not intended to limit the same to the exact details of the constructions set forth, and Vit embraces such changes, modifications, and equivalents of the parts and their formation and arrangement as come within the purview of the appended claims.

What is claimed is:

l. A motor boat hull, comprising:

(a) a plurality `of ski ribs of uniform width extending from the bow to the stern of the hull;

(b) each of said ribs having essentially vertical side walls and its underside having a cross section defining an obtuse inverted V;

(c) said ribs defining therebetween air duct channels also of ,uniform width and of suflcient depth to ,entrain air therein during movement of the hull over the surface of water.

2. A motor boat hull, comprising:

(a) a plurality of ski ribs of uniform width extending from the bow to the stern of the hull;

(b) each of said ribs having essentially vertical side walls and its underside having a cross section defining an obtuse inverted V;

(c) said ribs defining therebetween air duct channels also of uniform Width and of sufficient depth to entrain air therein during movement of the hull over the surface of Water;

(d) and means for mounting a motor to dispose its propeller in line with a selected ski rib, said selected ski rib having a width at least equal to the diameter of said propeller.

3. A motor boat hull, comprising:

(a) a plurality of ski ribs of uniform width extending from the bow to the stern of the hull;

(b) each of said ribs having essentially vertical side walls and its underside having a cross section defining an -obtuse inverted V;

(c) said ribs defining therebetween air duct channels yalso of uniform width and .of sufficient depth to entrain .air therein during movement of the hull over the surface of water;

(d) and sponsons laterally of said ski ribs having par- :allel confronting sides.

4. A motor boat hull structure, comprising:

(a) an outer hull including a bottom having a plurality of external ski ribs forming internal channels and separated by external channels forming internal ribs, the lateral sides of said ski ribs being essentially vertical and the cross portions of said external channels and internal ribs being essentially fiat, and defining a common plane, the underside of each ski rib defining in cross section an obtuse V, said ski ribs and external channels extending longitudinally from bow to stern of said outer hull and being uniform in width;

(b) an inner hull fitted within and bonded to said outer hull including a bottom extending over said internal ribs and bridging said internal channels to form therewith longitudinal cavities;

(c) and a rigid foamed plastic filling said cavities.

5. A motor boat hull structure, comprising:

(a) an outer hull including a bottom having a plurality of external ski ribs forming internal channels and separated by external channels forming internal ribs, the lateral sides of said ski ribs being essential vertical and the cross portions of said external channels and internal ribs being essentially flat, and defining a common plane, the underside of each ski rib defining in cross section an obtuse V, said ski ribs and external channels extending longitudinally from bow to stern of said outer hull and being uniform in width;

(b) A pair of sponsons laterally of and projecting below said ski ribs, said sponsons also forming internal channels;

(c) an inner hull fitted within and bonded to said outer hull, said inner hull including a bottom portion overlying and bonded to said internal ribs, and bridging said internal channels to form therewith longitudinal extending cav1t1es;

(d) and a rigid foamed plastic filling said cavities.

6. A motor boat hull, comprising:

(a) a plurality of ski ribs of uniform width extending from the bow to the stern of the hull;

b) said ribs defining therebetween air duct channels also of uniform width and of sufiicient depth to entrain air therein during movement of the hull over the surface of water;

(c) sponsons at the lateral sides of said ski ribs, said sponsons being of greater width than said ski ribs, the laterally outer sides of said sponsons sloping outwardly and upwardly, said sponsons having portions adjacent their forward ends of greater depth than said ski ribs, and rearward portions equal in depth to said ski ribs;

(4) the bow of said hull being upturned and the forward ends of said ski ribs and sponsons sloping upwardly, and progressively reduced in depth to merge into the surface of said bow, said ski ribs otherwise being uniform in depth.

7. A motor boat hull, comprising:

(a) a plurality of ski ribs of uniform width extending from the bow to the stern of the hull;

(b) each of said ski ribs having essentially vertical side walls and its underside having a cross section dening an obtuse inverted V;

(c) sponsons at the lateral sides of said ski ribs, said sponsons being of greater width than said ski ribs, the laterally outer sides of said sponsons sloping outwardly and upwardly, said sponsons having portions adjacent their forward ends of greater depth than said ski ribs, and rearward portions equal in depth to said ski ribs;

(d) the bow of said hull being upturned and the forward ends of said ski ribs and sponsons sloping upward- 1y, and progressively reduced in depth to merge into the surface of said bow, said ski ribs otherwise being uniform in depth.

References Cited in the le of this patent UNITED STATES PATENTS 2,875,720 Hupp Mar. 3, 1959 2,988,034 Hunt June 13, 1961 2,995,104 Mills Aug. 8, 1961 FOREIGN PATENTS 95,360 Norway Ian. 18, 1960 

1. A MOTOR BOAT HULL, COMPRISING: (A) A PLURALITY OF SKI RIBS OF UNIFORM WIDTH EXTENDING FROM THE BOW TO THE STERN OF THE HULL; (B) EACH OF SAID RIBS HAVING ESSENTIALLY VERTICAL SIDE WALLS AND ITS UNDERSIDE HAVING A CROSS SECTION DEFINING AN OBTUSE INVERTED V; (C) SAID RIBS DEFINING THEREBETWEEN AIR DUCT CHANNELS ALSO OF UNIFORM WIDTH AND OF SUFFICIENT DEPTH TO ENTRAIN AIR THEREIN DURING MOVEMENT OF THE HULL OVER THE SURFACE OF WATER. 